This invention relates to hydraulic cylinders and more particularly to a piston and seal assembly especially suitable for use in a hydraulic cylinder and to a seal especially suitable for use in a piston and seal assembly.
In a hydraulic cylinder, it is imperative for the effective operation of the cylinder that adequate sealing be provided between the piston assembly and the bore of the cylinder. This sealing is necessary in order to ensure that pressure fluid does not leak past the piston in one direction, that air does not leak past the piston in the opposite direction, and that contaminants are kept out of the sealing interface to maintain an effective air and pressure fluid seal between the piston and the bore of the cylinder.
Prior art attempts to provide the pressure fluid, air, and contaminant sealing functions have typically consisted of one or more annular seals either disposed in an external annular groove in the piston or in an internal annular groove in the cylinder. However, the prior art sealing systems have either not provided an effective seal with respect to the air, pressure fluid, or contaminants, or have provided an effective seal only by the use of a complex and expensive multiple seal arrangement.